Published:
2 April 2014
Category:
Q&A
Darren asks this question, which is about sleeving a flex cable’s earth core, and whether this practice is allowed. It has been answered by the NICEIC (Theme – Cables, Wiring and Wiring Accessories):
This Q & A is one of thousands posted in our Technical Expertise area, and answered on a daily basis by our Voltimum Experts.
Question: Is it permissible to sleeve the earth core to use as a switch wire in a three-core flex cable?
I have read that this practice is frowned upon - it is acceptable for flex cables only, but not for singles. Is this so?
Answer: This provision is used on a flex where the cross-sectional area of the conductor of the circuit protective conductor (CPC) is equal to the live conductors of the flex.
However, the flex must be over-sleeved at its terminations, and consideration as to whether the cable requires a CPC for compliance with BS 7671 must be adhered to.
It is frowned upon as, ideally, a four-core flex should be used in the first instance to resolve the issue.
Please see the attached article for your reference to this matter. It can be downloaded using the 'Attachments' link below (PDF document – 3.5MB file size).
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